1. Atoms, Elements, and the Periodic Table

2. The Periodic Table The periodic table is arranged in columns and rows
Periodic means: Repeating according to a pattern
The periodic table is arranged in columns and rows
Columns go up and down (think of columns on a building)
Rows go from left to right

3. In your Bohr Model What patterns did we see? In each column and row….
Look at the number of
Shells
&
Outer Electrons

4. The Periodic Table (cont.) Groups or Families
Columns are called: Groups or Families There are 18 groups or families in the periodic table (today you will know four a lot better) Elements in the same group or family have the same number of valence electrons Valence electrons are the number of electrons in the outer most energy level Group 1 has 1 valence electron

5. The Periodic Table -Periods
Periods are the portion of the periodic table that go from left to right (think of when you write a sentence, you put a period at the end of the sentence.
There are 7 periods in the periodic table.
All elements in the same period, have the same number of energy shells.
Energy shells are where the electrons are located

6. Today you will look more closely at the families in the table

7. Groups and Families
The columns in the periodic table are called groups, or families.
Each group has the same number of outer shell electrons
Group 1: Alkali Metals
Group 2: Alkaline Earth Metals
Group 7: Halogens
Group 8: Noble Gases

8. How many valence electrons does each group have?
All elements in a group have the same number of outer shell, or valence electrons Valence electrons determine how an element will behave and what it bonds with
How many valence electrons does each group have?

9. Ion Charge (Ion Formed)
You should remember that 8 is great! Elements will either gain or lose electrons to try to have 8 Elements with 3 or less electrons will LOSE electrons Becoming _____________ Elements with 4 or more will GAIN electrons For Hydrogen and Helium, 2 is good too! They can’t possibly hold 8 electrons, so they are full at 2

10. Atoms Atoms are the building blocks of matter
The modern atomic model describes an atom as consisting of:
Nucleus that contains:
Protons, neutrons, and electrons outside of the nucleus

11. Sub-atomic Particles
Subatomic particles: Protons, neutrons, and electrons
Each element in the periodic table has its own specific number of protons

12. Atomic Number The atomic number is the number of protons in an element
Every atom of a specific element has the same number of protons
Example: Hydrogen has 1 proton
Carbon has 6 protons
Sulphur has ___________
Silver has _____________

13. Neutrons
Neutrons Found in the nucleus Have no charge (neutral)

14. Isotopes Isotopes are:
Elements having the same number of protons, but different numbers neutrons
Examples: Carbon 12, 6 protons+ 6 neutrons
Carbon 13, 6 protons+7 neutrons
Carbon 14, 6 protons + 8 neutrons

15. Mass Number
Mass number is the number of protons + neutrons in the nucleus of an atom The atomic mass number is the average of the isotopes found naturally. 1 AMU is the weight of a proton/neutron (these particles are almost equal in mass) and each 6000 times larger than an electron

16. Electrons
Electrons are found orbiting around the nucleus in electron clouds (we can call them shells) The exact location of electrons cannot be determined Electrons have a negative charge (-) In a neutral atom, the number of electrons= the number of protons

17. Electrons An atom that has gained or lost electrons is called and ion.
Ions carry an electric charge because the number of protons (positive) in them is not equal to the number of electrons (negative.)
The charge on an ion is shown on the symbol of an element by adding a superscript number followed by a plus or minus sign.

18. Using this information
We can make a Bohr model of each element:
Write down the atomic mass and atomic number
Calculate the number of protons, electrons and neutrons
Atomic number = # of protons, and #of electrons in an neutral element
Atomic mass – atomic number = the # of neutrons

19. Bohr models
3) Put the protons and neutrons in a circle to represent the nucleus
4) Fill the electrons into the energy shells
2 electrons fill the first shell
8 electrons fill the second
8 electrons fill the third
18 fill the fourth.